1. (Science: zoology) a blood-sucking dipterous fly, of the genus Culex, undergoing a metamorphosis in water. The females have a proboscis armed with needlelike organs for penetrating the skin of animals. These are wanting in the males. In America they are generally called mosquitoes. See mosquito.
2. Any fly resembling a Culex in form or habits; especially, in America, a small biting fly of the genus Simulium and allies, as the buffalo gnat, the black fly, etc.
(Science: zoology) gnat catcher, a bird that catches gnats. Gnat strainer, a person ostentatiously punctilious about trifles. Cf.
Origin: as. Gnaet.